Fifty feet! That's kraken on a bit!

Seriously, though, while most descriptions of the Kraken lean toward the cephalopod-like, there are other descriptions that make it reminiscent of the Greek Hydra. I've also read of giant turtles which sailors have assumed to be islands and actually landed on. But as soon as they light a cooking fire the creature, understandably, submerges, taking the shore party with it!

The Hollywood identification of the Kraken with the sea monster Cetus, sent by Poseidon to ravage the coast of Ethiopia until Perseus petrified it to save Andromeda, can be put down to our old friend ignoramus cinematicus americani. The same invasive species that puts Arthurian Knights in Medieval armour and has Musketeers duelling with foils rather than rapiers.